Ballast cleaner

ABSTRACT

Ballast cleaner mechanism carried by a railroad car along a railroad track in which an infeed conveyor supported on the car receives the dirty ballast and divides it into a multiplicity of substantially equal streams of ballast which are discharged laterally on opposite sides of the conveyor at predetermined locations along its length onto a similar plurality of shaker screens. The clean ballast from these screens is discharged onto a clean ballast conveyor, disposed beneath and generally parallel to the infeed conveyor for delivery to a suitable discharge point, while dirt conveyors disposed on opposite sides of and parallel to the clean ballast conveyor are located beneath the respective screens for reception and removal of the dirt sifted through the screens from the dirty ballast.

United States Patent [1 1 Speno et al.

[ 1 Aug. 19, 1975 1 1 BALLAST CLEANER [73] Assignee: Frank SpenoRailroad Ballast Cleaning Company, lnc., lthaca, N.Y.

22 Filed: Nov. 28, 1973 211 Appl. No.: 419,876

[52) US. Cl. 209/241; 209/421; 37/104; 171/16 [51] Int. Cl. B078 H00[58] Field of Search "37/104,107; 171/16', 209/420, 421 241, 240, 243,247, 254; 198/188, 66

156] References Cited UNITED STATES PATENTS 679,500 7/1901 Edison H209/241 X 1,575,352 3/1926 Maclaren. t. 198/188 X 1,793,339 2/1931 Elmer209/420 X 1,982,824 12/1934 Miltenberger t l t 198/188 2,718,959 9/1955Van Otteren 198/188 X 2,734,730 2/1956 Talboys l 171/16 3.366.238 H1968Holley l l 209/421 X 3,721,331 3/1973 Holbrook 198/66 FOREIGN PATENTS ORAPPLICATlONS 417,745 10/1934 United Kingdom 171/16 PrimaryLiraminer-Robert Halper Attorney, Agent, or Firm-Watson, Cole, Grindle &Watson [5 7 ABSTRACT Ballast cleaner mechanism carried by a railroad caralong a railroad track in which an infeed Conveyor supported on the carreceives the dirty ballast and divides it into a multiplicity ofsubstantially equal streams of ballast which are discharged laterally onopposite sides of the conveyor at predetermined locations along itslength onto a similar plurality of shaker screens. The clean ballastfrom these screens is discharged onto a clean ballast conveyor, disposedbeneath and generally parallel to the infeed conveyor for delivery to asuitable discharge point, while dirt conveyors disposed on oppositesides of and parallel to the clean ballast conveyor are located beneaththe respective screens for reception and removal of the dirt siftedthrough the screens from the dirty ballast.

1] Claims, 7 Drawing Figures PATENTED AUG 1 9 I975 Fig. 2

PATENTED AUG 1 91975 BALLAST CLEANER This invention relates toimprovements in a ballast cleaner of the type such as generallydisclosed in and exemplified by the prior Speno US Pat. Nos. I,-)5l,45lof Mar. 20, I934 and 3,316,666 of May 2. 1967.

BACKGROUND OF THE INVENTION In prior ballast cleaning machines, such asexemplified by the foregoing patents. the ballast cleaner was carried bya flat car to be pulled by a locomotive in the usual manner at acomparatively slow rate of speed. By means of suitable scoops carried byone or more cars in advance of the cleaning mechanism, the dirty ballastwas picked up from the road bed lying along the side of the track justbeyond the ends of the cross ties and delivered by suitable conveyingand feeding mechanism to the ballast cleaning machine or apparatus.

The ballast cleaning apparatus included a vibrating screen, generallyinclined in the direction of travel of the train to sift the dirtthrough said screen onto a suitable dirt discharge conveyor and todeliver the cleaned stone by gravity onto a suitable stone conveyor orconveyor system for return to the roadbed adjacent the ends of the ties.

In such prior machines, the entire volume of dirty ballast to be treatedwas delivered onto the single vibrating screen which, as abovementioned, was inclined in the direction of travel so as to achieve agravity feed of the ballast to the lower discharge end of the screen,while the screen was generally, substantially parallel to the bed of theflat car in a transverse or lateral direction, so as normally to behorizontal when proceeding along straight portions of the track.However. the super elevation of the tracks at curves resulted in alateral tilting of the vibrating screen, causing the ballast thereon togravitate to its low side and to reduce the screening area and capacity.

All of the ballast during the cleaning process was required to proceedover the same screening area, thereby limiting the capacity of theapparatus.

The invention has been conceived with the foregoing considerations inmind and has as its primary objects: to provide a ballast cleaner whichachieves a maximum cleaning capacity with the use of a minimum bulk ofmachinery and. in particular. which provides a maximum effectivescreening area within the space normally available on a common railroadflat car; to provide such apparatus which may fully utilize the entirescreening area, regardless of the tilting resulting from passage aroundcurves; and to provide such apparatus in which substantially equalportions of dirty ballast are simultaneously fed to and acted upon by aplurality of shaker conveyors. Also, it is an incidental object toprovide such a machine or apparatus in which the conveyor which normallydelivers the ballast simultaneously to the plurality of shaker screens,may readily be adapted to bypass these screens and instead to deliver itdirectly to the dirt discharge conveyor for discharge to a suitablelocation. somewhat remote from the track in the event it is intended tocompletely replace such ballast.

SUMMARY OF THE INVENTION In accordance with the present invention, theballast cleaner mechanism is adapted for transport along a railroadtrack by a generally conventional flat car and includes an infeedconveyor for carrying the dirty ballast generally horizontally andparallel to the rails, together with means for discharging the dirtyballast laterally from the infeed conveyor in substantially equalstreams at longitudinally spaced locations along the infeed conveyor.Shaker screens beneath the infeed conveyor at the respectivelongitudinally spaced locations receive said streams of dirty ballastand discharge it onto a common longitudinally moving clean ballastconveyor. Dirt conveyers extend longitudinally beneath the shakerscreens for reception and removal of the dirt from the respective saidscreens.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiment of theinvention is illustrated in detail in the accompanying drawings inwhich:

FIG. I is a plan view of a ballast cleaner in accordance with theinvention, supported on a generally conventional flat car for movementalong a railroad track.

FIG. 2 is a side elevation of said ballast cleaner.

FIG. 3 is an enlarged end elevation of one of the shaker screen units ofthe preferred embodiment, the various conveyors being shown in verticalsection.

FIG. 4 is an enlarged fragmentary side elevation at the intake end ofthe infeed conveyor and the adjacent shaker screen unit.

FIG. 5 is a sectional elevation substantially on the line 5-5 of FIG. 4,and;

FIG. 6 is a diagrammatic plan view showing the preferred geographicarrangement of the two rows of shaker screen units and their drivemechanisms.

FIG. 7 is an end view showing the respective drive mechanisms for two ofthe screen units in their respec tive rows.

Referring now in detail to the accompanying drawings. and moreparticularly to the general arrangement of components as illustratedmore or less diagrammatically in FIGS. 1 and 2, the letter A designatesa generally conventional flat car supported on flanged wheels forrolling movement along a railroad track defined by the parallel rails B.supported on cross ties C on a usual road bed, wherein the tiesthemselves are embedded in ballast, usually consisting of crushed rock,extending beneath the cross ties and outwardly a substantial distancebeyond their ends.

As is well known and as shown by the prior Speno US. Pat. Nos. I.95l,45land 3.316.666, above mentioned, the flat car A which carries the ballastcleaning mechanism of the invention, normally is part of a train ofseveral cars which are pulled by a locomotive at a comparatively slowrate of speed in a direction toward the left as seen in FIGS. 1 and 2.Through the use of suitable scoops carried by one or more cars inadvance of the flat car A, as exemplified in the said Speno patents.dirty ballast is picked up from the roadbed along the sides of the trackjust beyond the ends of the cross ties and delivered by suitableconveying mechanism, here represented fragmentarily by the discharge endof a supply conveyor D. which discharges into the generally conventionalinfeed hopper E for delivery onto and distribution completely across theinfeed conveyor F of the ballast cleaning mechanism of the invention.

The infeed conveyor F. includes means designated generally by the letterG for dividing the inflowing dirty ballast on the conveyor into aplurality of substantially uniform longitudinal bands or streams anddischarging the respective streams transversely at predeterminedlongitudinal locations, preferably on both lateral sides of thatconveyor.

Two rows of longitudinally aligned shaker screens H. respectively,beneath the opposite side edges of the infeed conveyor E are located atand beneath the respective discharge locations for simultaneousreception of the plurality of discharge streams of dirty ballast,whereby the entire plurality of shaker screens may simultaneouslyreceive and screen out the dirt from the dirty ballast.

The said screens are arranged to discharge the clean ballast beneath theinfeed conveyor F onto a clean ballast or stone conveyor J which extendsgenerally horizontally beneath and in substantial vertical registry withthe infeed conveyor F.

The clean ballast conveyor then discharges the clean ballast in aforward direction with respect to the travel of the car A for receptionin a generally conventional clean ballast return hopper K, more commonlyreferred to as a stone box, by which it is returned to the roadbed toreplace the dirty ballast previously scooped up for processing by theballast cleaner mechanism of the present invention.

Extending longitudinally beneath the respective rows of shaker screens Hare dirt conveyors L. These con veyors respectively are disposed onopposite, lateral sides of the centrally located clean ballast conveyorJ and preferably in substantially a common horizontal plane therewith,so that each dirt conveyor has its operative run disposed directlybeneath one row of the shaker screens H. The operative runs of therespective dirt conveyors carry the dirt rearwardly with respect to thetravel of the flat car A and deliver it onto intermediate dirt conveyorsM which elevate and discharge the dirt into a dirt hopper N for deliveryonto a dirt discharge conveyor P, which may be of generally conventionalconstruction and is therefore but diagrammatically illustrated. Theillustrative form of dirt discharge conveyor P is of the boom type, theframe of which supports the dirt hopper N. The entire conveyor issupported for swinging movement about a substantially vertical axis atits receiving end extending through the center of the dirt hopper,whereby the latter may always be located properly for reception of thedirt discharged from the intermediate dirt conveyors M, At the sametime, the free end of the dirt discharge conveyor may be directed toeither lateral side of the track to discharge the dirt at a locationcomparatively remote from the roadbed.

As was earlier indicated, the supply conveyor D for the dirty ballastand the infeed hopper B may be conventionally constructed and arranged,their details constituting no part of the instant invention. The infeedconveyor F per se also may constitute a conventional belt conveyor, theopposite ends of which are supported around rolls such as 11 in FIGS. 3and 4, the shaft of each roll being suitably, rotatably supported byupright frame members such as 13-13 in FIG. 3. [t is to be understoodthat the upper operative horizontal run of the conveyor F is drivenrearwardly with respect to the direction of travel of the flat car A, orin a direction from left to right in FIGS. I and 4 of the drawings.

For assisting the infeed hopper E in distributing the incoming dirtyballast uniformly across the surface of the infeed conveyor F, there maybe provided suitable means, such as the driven eccentrics l0, engagingthe under surface of the operative run of the conveyor for impartingvertical vibration thereto.

The means for dividing and deflecting the conveyed dirty ballast, so asto discharge it at predetermined longitudinal locations from oppositesides of the conveyor, is here exemplified as a series of uniformlyspaced, parallel and vertical divider plates or partitions l5, fixedlysupported above the operative run of the conveyor F to define aplurality of parallel troughs of uniform width through whichsubstantially equal amounts of dirty stone are conveyed and divided intoequal portions.

For laterally discharging the said portions from opposite sides of theconveyor F, each partition 15 merges with and terminates in atransversely outwardly directed downstream end portion in the form of adeflector 16. The said deflectors are spaced uniformly in a longitudinaldirection along the conveyor to thus define a uniformly spaced series ofpredetermined discharge locations, said locations along each side of theconveyor being respectively located immediately above the respectiveshaker screens H of the row of shaker screens extending along itsrespective side.

The rows of shaker screens H in the preferred embodiment are supportedby a rigid framework consisting of longitudinal rows ofupright'standards 17 anchored to the floor or deck of the flat car A andtied together at their upper ends by longitudinal and transversehorizontal beams 18 and 19, respectively, as best illustrated in FIGS. 3and 4. Also, medially of the height of the standards 17 of eachtransversely opposed pair, the same are interconnected by a transversebeam 20.

The shaker screens H of the respective rows of such screens slopedownwardly and inwardly toward the longitudinal center line of the car Awith their lower discharge end over the clean ballast conveyor so thatthe ballast, after having had the dirt sifted therefrom through theseveral shaker screens of the respective conveyors, is delivered ontothe clean ballast return hopper or stonebox K and eventual return to theroadbed.

In each inclined shaker screen unit, the perforated screen 21 issupported in a rigid framework, including relatively longitudinallyspaced channel members defining vertical end walls 22. Each end wall isswingably suspended by relatively parallel links 23 for horizontalvibration which is imparted thereto from any suitable drive means.

Such drive means includes an eccentric shaft 24 rotatably supported inthe shaker frame as shown in FIGS. 3, 4 and 5. Each shaft 24 has keyedthereon a sheave wheel 25 through which rotary motion may be imparted tothe shaft 24 by way of a flexible drive from a suitable power sourcesupported by the rigid shaker frame.

The eccentric shaft 24 for each shaker unit has a pair of eccentrics 28and 29 at each end thereof. The eccentrics 28 transmit vibration throughconnecting rods 30 to the left hand shaker unit screen A of eachtransversely opposed pair of such units. To this end, the connectingrods 30 are provided at one end with bearings 31 which are joumalled onthe respective eccentrics 28, while at its opposite end each connectingrod has a bearing 32 joumalled on a cross shaft 33 afiixed to itsassociated shaker unit H.

Similarly, the eccentrics 29 of each cross shaft are connected by theconnecting rods 30' to cross shafts 33' of the shaker units of thetransversely opposed row of such units.

Preferably the eccentrics 28 are located in opposite phase to theeccentrics 29 so that each pair of relatively transversely opposedshaker screens will be caused to vibrate in opposite phase to eachother, whereby the vibrations ofone row of said units will be inopposition to and substantially cancel the vibrations of the other rowand thus greatly reduce the resulting stresses on the supporting framestructure and the flat car A.

In order to permit the disposition of the greatest possible number ofshaker units on a flat car A, it is desirable as shown in FIG. 6, thatthe eccentric shafts 24 of adjacent shaker screen units and their driveshafts 25, be relatively laterally offset with respect to each other.

The clean ballast conveyor J onto which the clean ballast is deliveredfrom both rows of shaker screens, and also the dirt conveyors LL, mayconveniently comprise conventional belt conveyors driven in any suitablemanner, the details of the conveyors and their drive means constitutingno part of the present invention and thus not being shown or describedin detail.

OPERATION The mode of operation of the preferred embodiment, which isbelieved to be readily apparent from the accompanying drawings and theforegoing detailed description, is as follows: Dirty ballast deliveredto the ballast cleaner by the supply conveyor D is received in thehopper E and delivered thereby substantially across the entire surfacethe infeed conveyor F, such distribution across the surface of theinfeed conveyor being assisted by vibration of the receiving end of thatconveyor by means of the rotating eccentrics 10. The supply of dirtyballast is then carried along by the operative upper run of the conveyorF in a direction from left to right as seen in FIGS. 1, 2 and 4. Duringits movement on the conveyor, the dirty ballast is divided by thelongitudinal partitions into a plurality of substantially equal bands orstreams which are discharged from opposite sides of the conveyor atpredetermined locations determined by the deflectors 16.

The discharged streams of dirty ballast are thus received upon therespective shaker screens H of each of the two rows of said shakerscreens respectively on opposite sides of the infeed conveyor. Afterbeing cleaned by sifting of the dirt therefrom, the clean ballast fromboth rows of conveyors is discharged by gravity onto the common cleanballast conveyor J for delivery to the stone box K and return to theroadbed, to replace the dirty stone originally scooped up therefrom.

Because of the advantageous arrangement and combination of the infeedconveyor, the longitudinal rows of shaker screens therebeneath, alldischarging onto the common clean ballast conveyor and theirrespectively associated dirty conveyors, it will be readily apparentthat the ballast cleaner of the invention is capable of achieving anextremely efiicient and rapid cleaning action on a large volume of dirtyballast. It will be particularly apparent that because of the foregoingarrangement and combination, there is achieved a maximum cleaningcapacity through the use ofa maximum effective screening area, and yetthe space requirements for such apparatus are no greater than is normally required in less efficient types of ballast cleaners as heretoforeknown in the prior art.

Moreover, it is to be particularly noted that because of the use of thelongitudinal partitions or dividers 15 in association with the infeedconveyor, and the fact that the slope or inclination of each shakerscreen is substantially greater than the tilt that will be imparted tothe flat car A during movement around a curve, any such tilting willhave no appreciable effect on reducing the amount of screening areawhich is in effective use at any time and moreover will not detract fromthe substantially equal distribution of dirty ballast to the respectiveshaker screens, so that all of them may continue to operate bothuniformly and efficiently.

In this application, I have shown and described only the preferredembodiment of the invention, simply by way of illustration of thepractice of the invention, but without any intention of limiting it tothe specific embodiment and details thereof, herein disclosed. Quiteobviously, the invention is capable of other and different embodimentsand its several details may be moditied in various respects by personsskilled in the art, all without departing from the invention as definedin the accompanying claims.

What is claimed is:

l. A ballast cleaner for transport by a railroad car along the rails ofa railroad track comprising: An infeed conveyor for dirty ballastsupported on said car and having an operative run at an elevationsubstantially above said car, moving longitudinally of the car in adirection parallel to the said rails; means for removing dirty ballastin lateral directions continuously and in substantially equal streamsfrom said conveyor at locations spaced apart longitudinally thereof; alongitudinal row of shaker screens beneath the infeed conveyor at therespective said locations for reception of the respective increments ofdirty ballast; said screens all having discharge ends beneath saidinfeed conveyor for discharge of cleaned ballast, transversely to theinfeed conveyor movement; a longitudinally moving a clean ballastconveyor disposed for simultaneous reception of clean ballast from thedischarge ends of the respective said shaker screens and for conveyingsaid clean ballast to a predetermined discharge point; and a dirtconveyor extending longitudinally beneath all of the screens of said rowfor reception and removal of the dirt sifted through said screens.

2. A ballast cleaner as defined in claim 1 including two said rows ofshaker screens beneath said infeed conveyor both discharging cleanballast onto said clean ballast conveyor, and a pair of said dirtconveyors disposed respectively beneath the said rows of screens onopposite sides of said clean ballast conveyor.

3. A ballast cleaner as defined in claim 2 in which said clean ballastconveyor and said dirt conveyors are all disposed at a common horizontallevel.

4. A ballast cleaner to be carried by a railroad car along a railroadtrack for treating the ballast from the road bed of said track,comprising: an infeed conveyor supported on said car for receiving andtransporting dirty ballast from the road bed, said conveyor having anoperative run at an elevation above the car and moving longitudinallythereof in a direction parallel to the railroad track; means forsimultaneously deflecting the conveyed dirty ballast in opposite lateraldirections from said conveyor at each of a plurality of predeterminedlongitudinal locations on opposite sides thereof; two rows oflongitudinally aligned shaker screens, said rows of shaker screens beinglocated respectively beneath the opposite sides of said infeed conveyorat said respective predetermined longitudinal locations for simultaneousreception of said dirty ballast; each of said shaker screens dischargingclean ballast beneath said infeed conveyor; and a longitudinally movingclean ballast conveyor disposed beneath said infeed conveyor and betweensaid rows of shaker screens for reception of clean ballast from therespective said shaker screens and for conveying said clean ballastlongitudinally to a point of discharge.

5. A ballast cleaner as defined in claim 4 including longitudinallymoving dirt conveyors disposed on opposite side of and parallel to saidclean ballast conveyor beneath the respective shaker screens forreception and removal of the dirt sifted through said screens.

6. A ballast cleaner as defined in claim 5 in which said dirt conveyorsmove in an opposite direction from said clean ballast conveyor.

7. A ballast cleaner for transport along the rails of a railroad trackcomprising: an infeed conveyor for dirty ballast having an operativegenerally horizontal run moving longitudinally in a direction parallelto the said rails; means for simultaneously deflecting the dirty ballastlaterally from the infeed conveyor in substantially equal streams atlongitudinally spaced locations along the infeed conveyor; a row oflongitudinally aligned shaker screens beneath said infeed conveyor atthe respective longitudinally spaced locations for simultaneouslyreceiving the streams of dirty ballast from said infeed conveyor; saidshaker sew I iping downwardly transversely to the sin: mfced conveyorand having discharge ends aligned longitudinally at a common level; anda longitudinally moving stone conveyor disposed for reception of thecleaned ballast from all of said screens and for conveying said cleanedballast to a predetermined discharge point.

8. A ballast cleaner as defined in claim 7 including a dirt conveyorhaving an operative run beneath said row of shaker screens and movingparallel to said clean ballast conveyor for reception and removal ofdirt sifted through said screens.

9. A ballast cleaner as defined in claim 8 in which all of saidconveyors and said row of shaker screens are substantiallylongitudinally coextensive said clean ballast conveyor and said dirtconveyor being at a common horizontal level, whereby to achieve acompact arrangement of said ballast cleaner.

10. A ballast cleaner as defined in claim 8 in which said clean ballastconveyor is spaced beneath and parallel to said infeed conveyor, thedischarge ends of said shaker screens projecting between the said dirtyballast and clean ballast conveyors.

11. A ballast cleaner as defined in claim 10. wherein said dischargeends of the shaker screens project between the said dirty ballastconveyor and stone conveyor from opposite lateral sides of therespective conveyors.

1. A BALLAST CLEANER FOR TRANSPORT BY A RAILROAD CAR ALONG THE RAILS OFA RAILROAD TRACK COMPRISING: AN INFEED CONVEYOR FOR DIRTY BALLASTSUPPORTED ON SAID CAR AND HAVING AN OPERATIVE RUN AT AN ELEVATIONSUBSTANTIALLY ABOVE SAID CAR, MOVING LONGITUDINALLY OF THE CAR IN ADIRECTION PARALLEL TO THE SAID RAILS: MEANS FOR REMOVING DIRTY BALLASTIN LATERAL DIRECTIONS CONTINOUSLY AND IN SUBSTANTIALLY EQUAL STREAMSFROM SAID CONVEYOR AT LOCATIONS SPACED APART LONGITUDINALLY THEREOF, ALONGITUDINAL ROW OF SHAKER SCREENS BENEATH THE INFEED CONVEYOR AT THERESPECTIVE SAID LOCATIONS FOR RECEPTION OF THE RESPECTIVE INCREMENTS OFDIRTY BALLAST, SAID SCREENS ALL HAVING DISCHARGE ENDS BENEATH SAIDINFEED CONVEYOR FOR DISCHARGE OF CLEANED BALLAST, TRANSVERSELY TO THEINFEED CONVEYOR MOVEMENT, A LONGITUDINALLY RECEPTION OF CLEAN BALLASTFROM THE DISCHARGE ENDS OF THE RESPECTIVE SAID SHAKER SCREENS AND FORCONVEYING SAID CLEAN BALLAST TO A PREDETERMINED DISCHARGE POINT, AND ADIRT CONVEYOR EXTENDING LONGITUDINALLY BENEATH ALL OF THE SCREENS OFMOVING A CLEAN BALLAST CONVEYOR DISPOSED FOR SIMULTANEOUS SAID ROW FORRECEPTION AND REMOVAL OF THE DIRT SIFTED THROUGH
 2. A ballast cleaner asdefined in claim 1 including two said rows of shaker screens beneathsaid infeed conveyor both discharging clean ballast onto said cleanballast conveyor, and a pair of said dirt conveyors disposedrespectively beneath the said rows of screens on opposite sides of saidclean ballast conveyor.
 3. A ballast cleaner as defined in claim 2 inwhich said clean ballast conveyor and said dirt conveyors are alldisposed at a common horizontal level.
 4. A ballast cleaner to becarried by a railroad car along a railroad track for treating theballast from the road bed of said track, comprising: an infeed conveyorsupported on said car for receiving and transporting dirty ballast fromthe road bed, said conveyor having an operative run at an elevationabove the car and moving longitudinally thereof in a direction parallelto the railroad track; means for simultaneously deflecting the conveyeddirty ballast in opposite lateral directions from said conveyor at eachof a plurality of predetermined longitudinal locations on opposite sidesthereof; two rows of longitudinally aligned shaker screens, said rows ofshaker screens being located respectively beneath the opposite sides ofsaid infeed conveyor at said respective predetermined longitudinallocations for simultaneous reception of said dirty ballast; each of saidshaker screens discharging clean ballast beneath said infeed conveyor;and a longitudinally moving clean ballast conveyor disposed beneath saidinfeed conveyor and between said rows of shaker screens for reception ofclean ballast from the respective said shaker screens and for conveyingsaid clean ballast longitudinally to a point of discharge.
 5. A ballastcleaner as defined in claim 4 including longitudinally moving dirtconveyors disposed on opposite side of and parallel to said cleanballast conveyor beneath the respective shaker screens for reception andremoval of the dirt sifted through said screens.
 6. A ballast cleaner asdefined in claim 5 in which said dirt conveyors move in an oppositedirection from said clean ballast conveyor.
 7. A ballast cleaner fortransport along the rails of a railroad track comprising: an infeedconveyor for dirty ballast having an operative generally horizontal runmoving longitudinally in a direction parallel to the said rails; meansfor simultaneously deflecting the dirty ballast laterally from theinfeed conveyor in substantially equal streams at longitudinally spacedlocations along the infeed conveyor; a row of longitudinally alignedshaker screens beneath said infeed conveyor at the respectivelongitudinally spaced locations for simultaneously receiving the streamsof dirty ballast from said infeed conveyor; said shaker screens slopingdownwardly transversely to the said infeed conveyor and having dischargeends aligned longitudinally at a common level; and a longitudinallymoving stone conveyor disposed for reception of the cleaned ballast fromall of said screens and for conveying saiD cleaned ballast to apredetermined discharge point.
 8. A ballast cleaner as defined in claim7 including a dirt conveyor having an operative run beneath said row ofshaker screens and moving parallel to said clean ballast conveyor forreception and removal of dirt sifted through said screens.
 9. A ballastcleaner as defined in claim 8 in which all of said conveyors and saidrow of shaker screens are substantially longitudinally coextensive, saidclean ballast conveyor and said dirt conveyor being at a commonhorizontal level, whereby to achieve a compact arrangement of saidballast cleaner.
 10. A ballast cleaner as defined in claim 8 in whichsaid clean ballast conveyor is spaced beneath and parallel to saidinfeed conveyor, the discharge ends of said shaker screens projectingbetween the said dirty ballast and clean ballast conveyors.
 11. Aballast cleaner as defined in claim 10, wherein said discharge ends ofthe shaker screens project between the said dirty ballast conveyor andstone conveyor from opposite lateral sides of the respective conveyors.